Problem: The grades on a history midterm at Almond are normally distributed with $\mu = 82$ and $\sigma = 5.0$. Nadia earned a $68$ on the exam. Find the z-score for Nadia's exam grade. Round to two decimal places.
Answer: A z-score is defined as the number of standard deviations a specific point is away from the mean We can calculate the z-score for Nadia's exam grade by subtracting the mean $(\mu)$ from her grade and then dividing by the standard deviation $(\sigma)$ $ { z = \dfrac{x - {\mu}}{{\sigma}}} $ $ { z = \dfrac{68 - {82}}{{5.0}}} $ ${ z \approx -2.80}$ The z-score is $-2.80$. In other words, Nadia's score was $2.80$ standard deviations below the mean.